The invention relates to a method for the insufflation of a CO.sub.2 gas in a biological body, in which the pressure of the gas is reduced by means of at least one pressure reducing stage and is subsequently insufflated into the biological body, as well as to a heating apparatus for a pressure-reduced CO.sub.2 gas to be introduced into a biological body and which is insufflated into the body by means of an insufflator and a hose line emanating therefrom.
In the case of medical examinations or surgical interventions in the vicinity of the abdomen or thorax pelviscopy, use is made of insufflators with the aid of which a gas, e.g. CO.sub.2 or N.sub.2 O gas, is insufflated into the corresponding body cavity. This gas supplied at a relatively low overpressure of e.g. 14 to 50 mm/Hg to the corresponding body cavity and which is postoperatively resorbed by the body, makes it possible for the surgeon to endoscopically examine or surgically treat the corresponding organ or tissue area. Therefore such insufflators are adequately known in modern endoscopic surgery.
One problem which has not been solved up to now is that the gas reduced to the necessary, desired pressure by means of different pressure reducing stages at present has a temperature of 16.degree. to 24.degree. C. at the outflow nipple or fitting of the insufflator and is insufflated into the body at this temperature, which medically speaking is well below the body temperature.
This relatively low temperature is due to the fact that the gas is supplied from a liquid pressure cylinder at a pressure of approximately 60 bar and ambient temperature of approximately 23.degree. C. to the insufflation hose. The gas expanded from liquid by pressure reduction over several stages initially leads to an extreme temperature reduction due to the volume expansion of the gas to well below 0.degree. C.
It is admittedly possible within the lines of the insufflator and in particular in the insufflation hose, to raise the temperature to approximately 21.degree. C., so that the CO.sub.2 gas insufflated into the body roughly has this temperature, but it is still well below the body temperature of 37.degree. C.
The temperature difference between the insufflated gas and the tissue with a body temperature of 37.degree. C. can lead to catarrhal effects in the abdomen and therefore to pains of a non-specific nature, which have not yet been accurately medically diagnosed.
Consequently there is a medical need to equal out this temperature difference between the insufflated gas and the body temperature in order to avoid any non-specific medical discomfort for the patient.
Attempts to heat the CO.sub.2 gas during an insufflation process by means of a hot water bath, by passing the gas through a V2A line at a temperature of approximately 50.degree. C., have a poor efficiency during heating, while the line length, too, is unsatisfactory.
Another alternative of passing the gas through a small heating box containing a heating star, had to be abandoned for various reasons. The problems were in particular that the gas can be excessively heated, which can particularly occur with a very low gas flow and a subsequently necessary high flow.
In addition, the heating box cannot be used as it is not medically sterile, because the moisture and heat formed in the said box would constitute an ideal medium for fungus, so that there would be a considerable contamination risk.
In addition, there are obviously the medically necessary sterilization criteria, the equipment being exposed to a temperature of approximately 134.degree. C. e.g. in the case of steam sterilization. A gas sterilization would also be conceivable, e.g. with ethylene oxide at approximately 60.degree. C., but this would have to take place over a long period of time and this will not be allowed in the future.